Effects of substrate temperature on material and photovoltaic properties of magnetron-sputtered Sb ₂ Se ₃ thin films

We studied the material and photovoltaic properties of Sb ₂ Se ₃ thin films fabricated by a magnetron-sputtering method at different substrate temperatures. The films had good crystallinity at substrate temperatures over 300° C. The band-gap energies between 1.1 and 1.5 eV of the films, which were obtained by transmittance measurements, initially decreased and then increased slowly with increasing temperature. Solar cells based on the films with structures of ITO∕CdS∕Sb ₂ Se ₃ ∕Au were fabricated, and the substrate temperature had significant effects on the device performance. Low crystal quality at low temperature resulted in a low short-circuit current (J _sc ), while high temperature caused Se deficiency due to evaporation, which decreased the open-circuit voltage (V _oc ). The best solar cell performance achieved an efficiency of 0.84% with a V _oc of 0.27 V and J _sc of 9.47 mA∕cm ² when the substrate temperature was 325°C.